Re: Why isn't the other part of the graph taken?

It cannot be "included" in the answer because the two together give all of which is not invertible. Both -2 and 2 are mapped to 4 so there is not unique inverse for 4. However, that is an alternate answer. " for " has inverse while " for " has inverse . If fact, there are infinitely many correct answers to this problem. " for " is invertible and so is " for ".